The invention relates to a flexible bearing bar disposed, in particular, in an auxiliary sheet pile carrier for a pile change in a sheet-fed printing machine and is described, for example, in the published German Patent Document DE 42 11 353 C2 (which corresponds to U.S. Pat. No. 5,295,681). The flexible construction permits the bearing bar to be accommodated in a space-saving manner in a non-loaded, non-functional position within the sheet-fed printing machine. On the other hand, however, the bearing bar must have sufficient load-bearing capacity and dimensional stability in a predetermined, loaded load-bearing position, wherein it bears a residual pile during the pile change. The bearing bar is usually aligned rectilinearly in the load-bearing position, although it may also have, if necessary or desirable, a predetermined curvature, in the load-bearing position, which has to be maintained.
The conventional bearing bar is constructed as a chain with a multiplicity of chain links which are connected to one another via joints and, in a conventional manner, is deflectable and windable up in a direction to one side, while, with the chain in an outstretched alignment, the chain links are in contact with the front sides thereof and thus prevent deflection and winding up in the direction towards the other side. Load-bearing elements in the form of a chain which is flexurally stiff on one side have also become known heretofore from the published German Patent Documents DE 83 16 127 U1, DE 42 15 791 A1 and DE 44 24 287 A1, it being noted that, in the case of the last-mentioned document, a tensioning cable running along the chain is provided in order to stiffen the chain.
A bearing bar in the form of a chain, however, involves high outlay, in construction terms, because it is necessary to form a multiplicity of joints which connect the chain links to one another in an articulated and tension-resistant manner. Moreover, the chains are subject to a relatively high level of wear at the joints thereof, due to which the service life of the bearing bar is limited.
It is accordingly an object of the invention to provide a flexible bearing bar for accommodating a sheet pile in a sheet-processing machine, which is of straightforward construction and is subject to a minimal level of wear.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a flexible bearing bar comprising a flexurally soft tensile member carrying, on one side thereof, a multiplicity of thrust elements disposed successively in series and formed with respective contact surfaces, the tensile member being supportable on two supports, and contact surfaces being subjectible to a load acting between the supports, from the thrust elements in a direction towards the tensile member for keeping the contact surfaces, respectively, in contact with one another.
In accordance with another feature of the invention, the tensile member is a belt.
In accordance with another feature of the invention, the thrust elements are formed integrally with the tensile member.
In accordance with a further feature of the invention, the thrust elements are fastened to the tensile member.
In accordance with an added feature of the invention, the thrust elements are fastened adjustably to the tensile member.
In accordance with an additional feature of the invention, the thrust elements are securable in different positions in a longitudinal direction of the tensile member.
In accordance with yet another feature of the invention, the bearing bar includes a tensioning device for bracing the thrust elements against one another.
In accordance with yet a further feature of the invention, the tensioning device has a tensioning cable extending through through-passages formed in the thrust elements.
In accordance with yet an added feature of the invention, the bearing bar includes a protective sheath for covering the thrust elements.
In accordance with yet an additional feature of the invention, the protective sheath is extensible.
In accordance with still another feature of the invention, the bearing bar includes a protective sheath for covering the tensile member.
In accordance with still a further feature of the invention, the protective sheath for the tensile member is extensible.
In accordance with still an added feature of the invention, the thrust elements engage with one another in a formlocking manner on the contact surfaces thereof.
In accordance with still an additional feature of the invention, the bearing bar includes an engagement part formed on one of the contact surfaces and engageable in a recess formed in another contact surface associated therewith.
In accordance with another feature of the invention, respective contact surfaces of the thrust elements located in a respective end region of the bearing bar are planar and are inclined so that the ends thereof which are directed towards the tensile member are closer to a center of the bearing bar than the ends thereof which are directed away from the tensile member.
In accordance with a further feature of the invention, those of the contact surfaces which are closer to a respective end of the bearing bar are inclined to a more pronounced extent than those of the contact surfaces which are farther away from the respective end.
In accordance with an added feature of the invention, those of the contact surfaces of the thrust elements located in a respective end region of the bearing bar are curved so that, as viewed from a bearing-bar end associated with the end region, in a position thereof wherein the tensile member forms an underside of the bearing bar, they are curved concavely downwardly from the top side of the bearing bar.
In accordance with an additional feature of the invention, the curved contact surfaces are inclined so that the ends thereof which are directed towards the tensile member are closer to a center of the bearing bar than the ends thereof which are directed away from the tensile member.
In accordance with yet another feature of the invention, those curved and inclined contact surfaces which are closer to a respective end of the bearing bar are inclined to a more pronounced extent than those which are farther away from the respective end.
In accordance with yet a further feature of the invention, the curved contact surfaces constitute lateral-surface sections of imaginary cylinders.
In accordance with a concomitant feature of the invention, 21. The bearing bar according to claim 20, wherein a respective one of the imaginary cylinders has a cylinder axis which is located at least approximately in a region of that side of the tensile member which is directed away from the thrust elements.
Thus, in order to achieve the foregoing object, the invention provides a flexible bearing bar having a flexurally soft tensile member which, on one side, carries a multiplicity of thrust elements which are arranged successively in series, are formed with contact surfaces and, with the tensile member being supported on two supports and with the contact surfaces being subjected to a load acting between the supports, from the thrust elements in the direction of the tensile member, are in contact with one another.
The invention provides a flexible bearing bar which, rather than being made up of a multiplicity of individual chain links, has a tension-resistant, but flexurally soft tensile member, in particular, in the form of a relatively flexible belt, for example, made of metal, which determines the deflection properties of the bearing bar. On that side on which compressive stressing is produced as a result of transverse loading, due to the sheet pile which is to be accommodated, the tensile member carries a plurality of thrust elements, which are arranged successively in series so that in the predetermined load-bearing position of the bearing bar, for example, in the outstretched or straightened-out position of the latter, they abut one another on mutually facing contact surfaces and are supported against one another, with compressive stressing building up in the process, with the result that deflection of the bearing bar is prevented. Deflection of the bearing bar under the aforementioned transverse loading in the opposite direction, in contrast, is possible because, in this case, the thrust elements do not abut one another. In this regard, the bearing bar is of straightforward construction, and pin joints, as are usually provided in a chain, are avoided altogether.
The tensile member and the thrust elements may be prefabricated as separate components and then connected to one another. It is possible, in this configuration, for the thrust elements to be applied to the tensile member by a releasable fastening, for example, of a screw-connection, thereby providing the advantage of adjustably retaining the thrust elements on the tensile member. It is possible, in particular, for the thrust elements to be securable in different positions in the longitudinal direction of the tensile member, as a result of which the compression-element contact surfaces, which come into abutment with one another, can be adjusted.
An alternative configuration may provide that the tensile member and the thrust elements be constructed as a one-piece or integral component. A development of this configuration may provide for the bearing bar to be constructed from a multiplicity of thin lamellae located beside one another, in which case each lamella includes a layer of the tensile member and of the thrust elements and can be cut out of a corresponding panel or plate. one-piece or integral component. A development of this configuration may provide for the bearing bar to be constructed from a multiplicity of thin lamellae located beside one another, in which case each lamella includes a layer of the tensile member and of the compressive elements and can be cut out of a corresponding panel or plate.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a flexible bearing bar for accommodating a sheets pile in a sheet-processing machine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: